The synaptic organization of the vertebrate retina for color vision will be examined by light microscopy and electron microscopy. Whole cells will be characterized in Golgi preparations. Synaptic ultrastructure will be examined in freeze-fracture replicas. Cells will be identified functionally by monochromatic light-induced uptake of putative neurotransmitters and autoradiography. Morphogenesis and synaptogenesis will be followed in embryonic retinas. Structure will be analyzed also by three-dimensional reconstruction from serial sections with the aid of computer graphics methods. BIBLIOGRAPHIC REFERENCES: Stell, W.K. and F.I. Harosi 1976 Cone structure and visual pigment content in the retina of the goldfish. Vision Res., 16:647-657. Stell, W.K. 1976 Functional polarization of horizontal cell dendrites in goldfish retina. Invest. Ophthal., 15:895-909.